docs: changes to broadcast documentation
- move BroadcastReceiver info to developer guide. see cl/140402421
- add usage note to CONNECTIVITY_ACTION broadcast
bug:32533262
bug:33106411
Change-Id: Ic2aa517831d29418e0c42aa6fc1e7f9aeb50f802
diff --git a/core/java/android/content/BroadcastReceiver.java b/core/java/android/content/BroadcastReceiver.java
index 10e6fb2..a7a8615 100644
--- a/core/java/android/content/BroadcastReceiver.java
+++ b/core/java/android/content/BroadcastReceiver.java
@@ -27,189 +27,25 @@
import android.util.Slog;
/**
- * Base class for code that will receive intents sent by sendBroadcast().
- *
- * <p>If you don't need to send broadcasts across applications, consider using
- * this class with {@link android.support.v4.content.LocalBroadcastManager} instead
- * of the more general facilities described below. This will give you a much
- * more efficient implementation (no cross-process communication needed) and allow
- * you to avoid thinking about any security issues related to other applications
- * being able to receive or send your broadcasts.
+ * Base class for code that receives and handles broadcast intents sent by
+ * {@link android.content.Context#sendBroadcast(Intent)}.
*
* <p>You can either dynamically register an instance of this class with
* {@link Context#registerReceiver Context.registerReceiver()}
- * or statically publish an implementation through the
+ * or statically declare an implementation with the
* {@link android.R.styleable#AndroidManifestReceiver <receiver>}
* tag in your <code>AndroidManifest.xml</code>.
- *
- * <p><em><strong>Note:</strong></em>
- * If registering a receiver in your
- * {@link android.app.Activity#onResume() Activity.onResume()}
- * implementation, you should unregister it in
- * {@link android.app.Activity#onPause() Activity.onPause()}.
- * (You won't receive intents when paused,
- * and this will cut down on unnecessary system overhead). Do not unregister in
- * {@link android.app.Activity#onSaveInstanceState(android.os.Bundle) Activity.onSaveInstanceState()},
- * because this won't be called if the user moves back in the history
- * stack.
- *
- * <p>There are two major classes of broadcasts that can be received:</p>
- * <ul>
- * <li> <b>Normal broadcasts</b> (sent with {@link Context#sendBroadcast(Intent)
- * Context.sendBroadcast}) are completely asynchronous. All receivers of the
- * broadcast are run in an undefined order, often at the same time. This is
- * more efficient, but means that receivers cannot use the result or abort
- * APIs included here.
- * <li> <b>Ordered broadcasts</b> (sent with {@link Context#sendOrderedBroadcast(Intent, String)
- * Context.sendOrderedBroadcast}) are delivered to one receiver at a time.
- * As each receiver executes in turn, it can propagate a result to the next
- * receiver, or it can completely abort the broadcast so that it won't be passed
- * to other receivers. The order receivers run in can be controlled with the
- * {@link android.R.styleable#AndroidManifestIntentFilter_priority
- * android:priority} attribute of the matching intent-filter; receivers with
- * the same priority will be run in an arbitrary order.
- * </ul>
- *
- * <p>Even in the case of normal broadcasts, the system may in some
- * situations revert to delivering the broadcast one receiver at a time. In
- * particular, for receivers that may require the creation of a process, only
- * one will be run at a time to avoid overloading the system with new processes.
- * In this situation, however, the non-ordered semantics hold: these receivers still
- * cannot return results or abort their broadcast.</p>
- *
- * <p>Note that, although the Intent class is used for sending and receiving
- * these broadcasts, the Intent broadcast mechanism here is completely separate
- * from Intents that are used to start Activities with
- * {@link Context#startActivity Context.startActivity()}.
- * There is no way for a BroadcastReceiver
- * to see or capture Intents used with startActivity(); likewise, when
- * you broadcast an Intent, you will never find or start an Activity.
- * These two operations are semantically very different: starting an
- * Activity with an Intent is a foreground operation that modifies what the
- * user is currently interacting with; broadcasting an Intent is a background
- * operation that the user is not normally aware of.
- *
- * <p>The BroadcastReceiver class (when launched as a component through
- * a manifest's {@link android.R.styleable#AndroidManifestReceiver <receiver>}
- * tag) is an important part of an
- * <a href="{@docRoot}guide/topics/fundamentals.html#lcycles">application's overall lifecycle</a>.</p>
- *
- * <p>Topics covered here:
- * <ol>
- * <li><a href="#Security">Security</a>
- * <li><a href="#ReceiverLifecycle">Receiver Lifecycle</a>
- * <li><a href="#ProcessLifecycle">Process Lifecycle</a>
- * </ol>
*
* <div class="special reference">
* <h3>Developer Guides</h3>
- * <p>For information about how to use this class to receive and resolve intents, read the
- * <a href="{@docRoot}guide/topics/intents/intents-filters.html">Intents and Intent Filters</a>
- * developer guide.</p>
- * </div>
+ * <p>For more information about using BroadcastReceiver, read the
+ * <a href="{@docRoot}guide/components/broadcasts.html">Broadcasts</a> developer guide.</p></div>
*
- * <a name="Security"></a>
- * <h3>Security</h3>
- *
- * <p>Receivers used with the {@link Context} APIs are by their nature a
- * cross-application facility, so you must consider how other applications
- * may be able to abuse your use of them. Some things to consider are:
- *
- * <ul>
- * <li><p>The Intent namespace is global. Make sure that Intent action names and
- * other strings are written in a namespace you own, or else you may inadvertently
- * conflict with other applications.
- * <li><p>When you use {@link Context#registerReceiver(BroadcastReceiver, IntentFilter)},
- * <em>any</em> application may send broadcasts to that registered receiver. You can
- * control who can send broadcasts to it through permissions described below.
- * <li><p>When you publish a receiver in your application's manifest and specify
- * intent-filters for it, any other application can send broadcasts to it regardless
- * of the filters you specify. To prevent others from sending to it, make it
- * unavailable to them with <code>android:exported="false"</code>.
- * <li><p>When you use {@link Context#sendBroadcast(Intent)} or related methods,
- * normally any other application can receive these broadcasts. You can control who
- * can receive such broadcasts through permissions described below. Alternatively,
- * starting with {@link android.os.Build.VERSION_CODES#ICE_CREAM_SANDWICH}, you
- * can also safely restrict the broadcast to a single application with
- * {@link Intent#setPackage(String) Intent.setPackage}
- * </ul>
- *
- * <p>None of these issues exist when using
- * {@link android.support.v4.content.LocalBroadcastManager}, since intents
- * broadcast it never go outside of the current process.
- *
- * <p>Access permissions can be enforced by either the sender or receiver
- * of a broadcast.
- *
- * <p>To enforce a permission when sending, you supply a non-null
- * <var>permission</var> argument to
- * {@link Context#sendBroadcast(Intent, String)} or
- * {@link Context#sendOrderedBroadcast(Intent, String, BroadcastReceiver, android.os.Handler, int, String, Bundle)}.
- * Only receivers who have been granted this permission
- * (by requesting it with the
- * {@link android.R.styleable#AndroidManifestUsesPermission <uses-permission>}
- * tag in their <code>AndroidManifest.xml</code>) will be able to receive
- * the broadcast.
- *
- * <p>To enforce a permission when receiving, you supply a non-null
- * <var>permission</var> when registering your receiver -- either when calling
- * {@link Context#registerReceiver(BroadcastReceiver, IntentFilter, String, android.os.Handler)}
- * or in the static
- * {@link android.R.styleable#AndroidManifestReceiver <receiver>}
- * tag in your <code>AndroidManifest.xml</code>. Only broadcasters who have
- * been granted this permission (by requesting it with the
- * {@link android.R.styleable#AndroidManifestUsesPermission <uses-permission>}
- * tag in their <code>AndroidManifest.xml</code>) will be able to send an
- * Intent to the receiver.
- *
- * <p>See the <a href="{@docRoot}guide/topics/security/security.html">Security and Permissions</a>
- * document for more information on permissions and security in general.
- *
- * <a name="ReceiverLifecycle"></a>
- * <h3>Receiver Lifecycle</h3>
- *
- * <p>A BroadcastReceiver object is only valid for the duration of the call
- * to {@link #onReceive}. Once your code returns from this function,
- * the system considers the object to be finished and no longer active.
- *
- * <p>This has important repercussions to what you can do in an
- * {@link #onReceive} implementation: anything that requires asynchronous
- * operation is not available, because you will need to return from the
- * function to handle the asynchronous operation, but at that point the
- * BroadcastReceiver is no longer active and thus the system is free to kill
- * its process before the asynchronous operation completes.
- *
- * <p>In particular, you may <i>not</i> show a dialog or bind to a service from
- * within a BroadcastReceiver. For the former, you should instead use the
- * {@link android.app.NotificationManager} API. For the latter, you can
- * use {@link android.content.Context#startService Context.startService()} to
- * send a command to the service.
- *
- * <a name="ProcessLifecycle"></a>
- * <h3>Process Lifecycle</h3>
- *
- * <p>A process that is currently executing a BroadcastReceiver (that is,
- * currently running the code in its {@link #onReceive} method) is
- * considered to be a foreground process and will be kept running by the
- * system except under cases of extreme memory pressure.
- *
- * <p>Once you return from onReceive(), the BroadcastReceiver is no longer
- * active, and its hosting process is only as important as any other application
- * components that are running in it. This is especially important because if
- * that process was only hosting the BroadcastReceiver (a common case for
- * applications that the user has never or not recently interacted with), then
- * upon returning from onReceive() the system will consider its process
- * to be empty and aggressively kill it so that resources are available for other
- * more important processes.
- *
- * <p>This means that for longer-running operations you will often use
- * a {@link android.app.Service} in conjunction with a BroadcastReceiver to keep
- * the containing process active for the entire time of your operation.
*/
public abstract class BroadcastReceiver {
private PendingResult mPendingResult;
private boolean mDebugUnregister;
-
+
/**
* State for a result that is pending for a broadcast receiver. Returned
* by {@link BroadcastReceiver#goAsync() goAsync()}
@@ -218,7 +54,7 @@
* terminate; you must call {@link #finish()} once you are done with the
* broadcast. This allows you to process the broadcast off of the main
* thread of your app.
- *
+ *
* <p>Note on threading: the state inside of this class is not itself
* thread-safe, however you can use it from any thread if you properly
* sure that you do not have races. Typically this means you will hand
@@ -232,14 +68,14 @@
public static final int TYPE_REGISTERED = 1;
/** @hide */
public static final int TYPE_UNREGISTERED = 2;
-
+
final int mType;
final boolean mOrderedHint;
final boolean mInitialStickyHint;
final IBinder mToken;
final int mSendingUser;
final int mFlags;
-
+
int mResultCode;
String mResultData;
Bundle mResultExtras;
@@ -259,7 +95,7 @@
mSendingUser = userId;
mFlags = flags;
}
-
+
/**
* Version of {@link BroadcastReceiver#setResultCode(int)
* BroadcastReceiver.setResultCode(int)} for
@@ -331,7 +167,7 @@
mResultData = data;
mResultExtras = extras;
}
-
+
/**
* Version of {@link BroadcastReceiver#getAbortBroadcast()
* BroadcastReceiver.getAbortBroadcast()} for
@@ -350,7 +186,7 @@
checkSynchronousHint();
mAbortBroadcast = true;
}
-
+
/**
* Version of {@link BroadcastReceiver#clearAbortBroadcast()
* BroadcastReceiver.clearAbortBroadcast()} for
@@ -359,7 +195,7 @@
public final void clearAbortBroadcast() {
mAbortBroadcast = false;
}
-
+
/**
* Finish the broadcast. The current result will be sent and the
* next broadcast will proceed.
@@ -397,14 +233,14 @@
sendFinished(mgr);
}
}
-
+
/** @hide */
public void setExtrasClassLoader(ClassLoader cl) {
if (mResultExtras != null) {
mResultExtras.setClassLoader(cl);
}
}
-
+
/** @hide */
public void sendFinished(IActivityManager am) {
synchronized (this) {
@@ -412,7 +248,7 @@
throw new IllegalStateException("Broadcast already finished");
}
mFinished = true;
-
+
try {
if (mResultExtras != null) {
mResultExtras.setAllowFds(false);
@@ -448,7 +284,7 @@
Log.e("BroadcastReceiver", e.getMessage(), e);
}
}
-
+
public BroadcastReceiver() {
}
@@ -468,14 +304,15 @@
*
* <p><b>If this BroadcastReceiver was launched through a <receiver> tag,
* then the object is no longer alive after returning from this
- * function.</b> This means you should not perform any operations that
- * return a result to you asynchronously -- in particular, for interacting
- * with services, you should use
- * {@link Context#startService(Intent)} instead of
- * {@link Context#bindService(Intent, ServiceConnection, int)}. If you wish
- * to interact with a service that is already running, you can use
- * {@link #peekService}.
- *
+ * function.</b> This means you should not perform any operations that
+ * return a result to you asynchronously. If you need to perform any follow up
+ * background work, schedule a {@link android.app.job.JobService} with
+ * {@link android.app.job.JobScheduler}.
+ *
+ * If you wish to interact with a service that is already running and previously
+ * bound using {@link android.content.Context#bindService(Intent, ServiceConnection, int) bindService()},
+ * you can use {@link #peekService}.
+ *
* <p>The Intent filters used in {@link android.content.Context#registerReceiver}
* and in application manifests are <em>not</em> guaranteed to be exclusive. They
* are hints to the operating system about how to find suitable recipients. It is
@@ -483,7 +320,7 @@
* resolution. For this reason, {@link #onReceive(Context, Intent) onReceive()}
* implementations should respond only to known actions, ignoring any unexpected
* Intents that they may receive.
- *
+ *
* @param context The Context in which the receiver is running.
* @param intent The Intent being received.
*/
@@ -496,7 +333,7 @@
* responsive to the broadcast (finishing it within 10s), but does allow
* the implementation to move work related to it over to another thread
* to avoid glitching the main UI thread due to disk IO.
- *
+ *
* @return Returns a {@link PendingResult} representing the result of
* the active broadcast. The BroadcastRecord itself is no longer active;
* all data and other interaction must go through {@link PendingResult}
@@ -508,15 +345,20 @@
mPendingResult = null;
return res;
}
-
+
/**
- * Provide a binder to an already-running service. This method is synchronous
+ * Provide a binder to an already-bound service. This method is synchronous
* and will not start the target service if it is not present, so it is safe
* to call from {@link #onReceive}.
- *
+ *
+ * For peekService() to return a non null {@link android.os.IBinder} interface
+ * the service must have published it before. In other words some component
+ * must have called {@link android.content.Context#bindService(Intent, ServiceConnection, int)} on it.
+ *
* @param myContext The Context that had been passed to {@link #onReceive(Context, Intent)}
- * @param service The Intent indicating the service you wish to use. See {@link
- * Context#startService(Intent)} for more information.
+ * @param service Identifies the already-bound service you wish to use. See
+ * {@link android.content.Context#bindService(Intent, ServiceConnection, int)}
+ * for more information.
*/
public IBinder peekService(Context myContext, Intent service) {
IActivityManager am = ActivityManagerNative.getDefault();
@@ -538,13 +380,13 @@
* Activity {@link android.app.Activity#RESULT_CANCELED} and
* {@link android.app.Activity#RESULT_OK} constants, though the
* actual meaning of this value is ultimately up to the broadcaster.
- *
+ *
* <p class="note">This method does not work with non-ordered broadcasts such
* as those sent with {@link Context#sendBroadcast(Intent)
* Context.sendBroadcast}</p>
- *
+ *
* @param code The new result code.
- *
+ *
* @see #setResult(int, String, Bundle)
*/
public final void setResultCode(int code) {
@@ -554,7 +396,7 @@
/**
* Retrieve the current result code, as set by the previous receiver.
- *
+ *
* @return int The current result code.
*/
public final int getResultCode() {
@@ -567,13 +409,13 @@
* {@link Context#sendOrderedBroadcast(Intent, String)
* Context.sendOrderedBroadcast}. This is an arbitrary
* string whose interpretation is up to the broadcaster.
- *
+ *
* <p><strong>This method does not work with non-ordered broadcasts such
* as those sent with {@link Context#sendBroadcast(Intent)
* Context.sendBroadcast}</strong></p>
- *
+ *
* @param data The new result data; may be null.
- *
+ *
* @see #setResult(int, String, Bundle)
*/
public final void setResultData(String data) {
@@ -584,7 +426,7 @@
/**
* Retrieve the current result data, as set by the previous receiver.
* Often this is null.
- *
+ *
* @return String The current result data; may be null.
*/
public final String getResultData() {
@@ -599,13 +441,13 @@
* holding arbitrary data, whose interpretation is up to the
* broadcaster. Can be set to null. Calling this method completely
* replaces the current map (if any).
- *
+ *
* <p><strong>This method does not work with non-ordered broadcasts such
* as those sent with {@link Context#sendBroadcast(Intent)
* Context.sendBroadcast}</strong></p>
- *
+ *
* @param extras The new extra data map; may be null.
- *
+ *
* @see #setResult(int, String, Bundle)
*/
public final void setResultExtras(Bundle extras) {
@@ -617,11 +459,11 @@
* Retrieve the current result extra data, as set by the previous receiver.
* Any changes you make to the returned Map will be propagated to the next
* receiver.
- *
+ *
* @param makeMap If true then a new empty Map will be made for you if the
* current Map is null; if false you should be prepared to
* receive a null Map.
- *
+ *
* @return Map The current extras map.
*/
public final Bundle getResultExtras(boolean makeMap) {
@@ -640,11 +482,11 @@
* {@link Context#sendOrderedBroadcast(Intent, String)
* Context.sendOrderedBroadcast}. All current result data is replaced
* by the value given to this method.
- *
+ *
* <p><strong>This method does not work with non-ordered broadcasts such
* as those sent with {@link Context#sendBroadcast(Intent)
* Context.sendBroadcast}</strong></p>
- *
+ *
* @param code The new result code. Often uses the
* Activity {@link android.app.Activity#RESULT_CANCELED} and
* {@link android.app.Activity#RESULT_OK} constants, though the
@@ -662,11 +504,11 @@
mPendingResult.mResultData = data;
mPendingResult.mResultExtras = extras;
}
-
+
/**
* Returns the flag indicating whether or not this receiver should
* abort the current broadcast.
- *
+ *
* @return True if the broadcast should be aborted.
*/
public final boolean getAbortBroadcast() {
@@ -679,10 +521,10 @@
* {@link Context#sendOrderedBroadcast(Intent, String)
* Context.sendOrderedBroadcast}. This will prevent
* any other broadcast receivers from receiving the broadcast. It will still
- * call {@link #onReceive} of the BroadcastReceiver that the caller of
+ * call {@link #onReceive} of the BroadcastReceiver that the caller of
* {@link Context#sendOrderedBroadcast(Intent, String)
* Context.sendOrderedBroadcast} passed in.
- *
+ *
* <p><strong>This method does not work with non-ordered broadcasts such
* as those sent with {@link Context#sendBroadcast(Intent)
* Context.sendBroadcast}</strong></p>
@@ -691,7 +533,7 @@
checkSynchronousHint();
mPendingResult.mAbortBroadcast = true;
}
-
+
/**
* Clears the flag indicating that this receiver should abort the current
* broadcast.
@@ -701,7 +543,7 @@
mPendingResult.mAbortBroadcast = false;
}
}
-
+
/**
* Returns true if the receiver is currently processing an ordered
* broadcast.
@@ -709,7 +551,7 @@
public final boolean isOrderedBroadcast() {
return mPendingResult != null ? mPendingResult.mOrderedHint : false;
}
-
+
/**
* Returns true if the receiver is currently processing the initial
* value of a sticky broadcast -- that is, the value that was last
@@ -719,7 +561,7 @@
public final boolean isInitialStickyBroadcast() {
return mPendingResult != null ? mPendingResult.mInitialStickyHint : false;
}
-
+
/**
* For internal use, sets the hint about whether this BroadcastReceiver is
* running in ordered mode.
@@ -727,21 +569,21 @@
public final void setOrderedHint(boolean isOrdered) {
// Accidentally left in the SDK.
}
-
+
/**
* For internal use to set the result data that is active. @hide
*/
public final void setPendingResult(PendingResult result) {
mPendingResult = result;
}
-
+
/**
* For internal use to set the result data that is active. @hide
*/
public final PendingResult getPendingResult() {
return mPendingResult;
}
-
+
/** @hide */
public int getSendingUserId() {
return mPendingResult.mSendingUser;
@@ -761,19 +603,19 @@
public final void setDebugUnregister(boolean debug) {
mDebugUnregister = debug;
}
-
+
/**
* Return the last value given to {@link #setDebugUnregister}.
*/
public final boolean getDebugUnregister() {
return mDebugUnregister;
}
-
+
void checkSynchronousHint() {
if (mPendingResult == null) {
throw new IllegalStateException("Call while result is not pending");
}
-
+
// Note that we don't assert when receiving the initial sticky value,
// since that may have come from an ordered broadcast. We'll catch
// them later when the real broadcast happens again.
diff --git a/core/java/android/net/ConnectivityManager.java b/core/java/android/net/ConnectivityManager.java
index 0afb546..f3c7817 100644
--- a/core/java/android/net/ConnectivityManager.java
+++ b/core/java/android/net/ConnectivityManager.java
@@ -87,6 +87,13 @@
* sent as an extra; it should be consulted to see what kind of
* connectivity event occurred.
* <p/>
+ * Apps targeting Android 7.0 (API level 24) and higher do not receive this
+ * broadcast if they declare the broadcast receiver in their manifest. Apps
+ * will still receive broadcasts if they register their
+ * {@link android.content.BroadcastReceiver} with
+ * {@link android.content.Context#registerReceiver Context.registerReceiver()}
+ * and that context is still valid.
+ * <p/>
* If this is a connection that was the result of failing over from a
* disconnected network, then the FAILOVER_CONNECTION boolean extra is
* set to true.
